The moment in my childhood when I realized data reliant on self reporting was probably suspect:
I miss those two, they taught me so much.
Weekend moment of zen 4-15-12
Why career advice on the Internet can be total crap
I like nurses, though I’ve never wanted to be one. My mother’s a nurse, my sister will be in a year or so. Most of my best projects have been done in conjunction with nursing departments. Due to my proximity to lots and lots of nurses, I tend to hear a lot about the ups and downs of the profession.
Given that, this article annoyed the heck out of me.
The headline reads “How To Land A $60K Health Care Job With A Two-Year Degree”, and being curious about the salaries of those around me, I took a peak. I was stunned to see that the supposed “$60K job with 2 years of education” was nursing. As proof, they offered the average annual salary for RN’s as $67,000 (backed up by the BLS here. (The BLS actually used the median, which is slightly lower at $64,000). They went on to mention that nurses in Massachusetts make an average of $84,000 a year.
Now that all sounds awesome, but here’s what’s deceptive: RN is not a degree. RN is a license. Neither the Bureau of Labor Statistics nor this article differentiate between the salaries of those who get an RN after getting an associate’s degree, and those who get it after getting a bachelor’s degree. It turns out there’s a lot of debate over how much of a difference this makes, but I can definitely speak to that Massachusetts salary number. I work for one of the institutions that’s notorious for paying nurses extremely well. They do not hire nurses who don’t have a BSN. For most of the major Boston teaching hospitals, this is an increasing trend. The Institute of Medicine is calling for 80% of nurses to be BSN educated by 2020, and many hospitals are responding accordingly. Most management jobs are off limits to associate’s level nurses.
I’ll leave it to the nursing associations to debate whether all this is necessary or not, but I will bring up that taking an average of two different degrees with two different sets of job prospects and then not mentioning that it may be apples and oranges. Additionally, even when nurses and nurse managers make the same amount, it’s often because one is overtime eligible (and works nights and evenings) and one doesn’t. So overall, deceptive headline, designed to make people click on it.
Of course since I did click on it, I guess that worked.
Friday links for fun – 4.13.12
This will be completely lost on you if you’re not a Hunger Games fan, but the stats work/extrapolation is pretty damn impressive.
Professionally, I found this interesting….I can only get you the numbers, ma’am, I can’t make you use them wisely.
I haven’t talked much about small sample sizes, but this blog does.
These guys are my new heroes. They noticed a statistical error that kept popping up in neuro research, and then went back and figured out how often people were getting it wrong….half of the studies that could have got it wrong did. It’s a stat geeky read, but hears the story.
Age Bias and Polling Methods
A few years ago, in one of my research methods classes in grad school, a professor I had asked us to raise our hand if we had a cell phone.
Everyone raised their hands.
Then he asked people to keep their hands up if they had a land line as well.
Many hands went down.
For those left, he asked how many answered it regularly or had caller ID and screened calls.
Pretty much everyone.
This of course then led in to a discussion of political polling and how many of us had ever considered who was actually answering these questions. It was an interesting discussion, as pretty much the entire class admitted they would have self excluded. The Pew Research center suggests this was not an anomaly, and that this is actually a problem that’s becoming more acute in political polling.
While many large national polling organizations have started calling cell phones as well, on the state level this is not often corrected for. This can, and has, resulted in some inaccurate polls, as the sample of people home, with a landline, willing to answer a pollsters call, does not always reflect the general population. Actually, I think there’s good reason to question the representativeness of a sample willing to answer their phone for an unknown number, but that could be disputed (those interested enough to pick up the phone also might be more likely to actually go vote).
Anyway, none of this is new. What is new this (presidential) election cycle is that news organizations are now starting to put up stats on Twitter and Facebook status updates. I decided to take a look and see exactly how skewed these stats are, and found that Twitter is most popular in the 18-29 demographic. Of course, this is the least likely demographic to actually vote. Interestingly, the poll on Twitter usage did not include people under 18, but these are not excluded when they are compiling trends.
So two different ways of tracking elections, two different sets of flaws. Pick your poison.
Plans for next weekend….
I’m headed to a conference in Chicago next week, and I don’t know that I’ll be back in time for this, but it looks awesome.
There’s bad data, and then there’s data that’s just plain mean….
I’ve worked at teaching hospitals for pretty much my whole post-college career, so I generally heave a bit of a sigh when I hear the initials “IRB”. IRB’s (Institutional Review Board) are set up to protect patients and approve of research, but they also have power to reject proposed studies and cause lots of paperwork. Sometimes though, you need a good reminder of why they were invented.
Apparently, some scientists in the 1940’s tried to develop a pain scale based on burning people and rating the pain. Then, to make sure they had a good control, they burned pregnant women while in between contractions.
While it actually wasn’t a half bad way of figuring out what their numerical scale should look like, that is just WRONG. As a pregnant women, I can pretty confidently say that anyone coming at me with a flat iron during labor will be kicked. Hard.
Unethical gathering of data is not only not worth it, but also frequently wasted. In the study mentioned above, the data proved useless, as pain is too subjective to be really quantified. After this fiasco, it wouldn’t be until 2010 that someone came up with a really workable pain scale.
You can’t misquote a misquote
Yesterday I talked about sensational statistics and to always verify that there’s no missing adjectives that would change the statistic. It was thus a bit serendipitous that today I happened to hear a debate about a misquoted statistic, and whether the quote or the misquote was more accurate. It was on a podcast I listen to, and it was about a month old (sometimes I don’t keep up well).
It was happening around the time the contraception debate was at it’s most furious (see what I did there? It was a federally mandated coverage of contraception debate, to give you all the adjectives). Anyway, at the time the statistic about the prevalence of birth control usage among Catholic women was getting tossed around quite a bit. The statistic, in it’s most detailed form, is this: 98% of self-identified Catholic women of child bearing age who are sexually active have used a contraceptive method other than natural family planning at some point in their lives.
Now, this stat rarely got quoted in it’s entirety. First, I always think designating that the religions is self identified is important. The women answering this survey didn’t have to clarify if they thought they were good Catholics, just Catholic. Second, the “sexually active” got glossed over as well, despite the fact that it probably cuts down the numbers at least a bit (for young adult Catholics, to approximately 89% of respondents). Third, “at some point”. The study’s authors have justified this qualifier by arguing that if a woman is on birth control for years, then decides to start trying to have children and goes off of it, she would have been excluded. Critics have argued that this strategy was designed to include women who may have tried it, decided it was wrong, and stopped. Both have a point.
That being said, I most often heard this being quoted as “98% of Catholic women use birth control” or sometimes even “98% of Catholics use birth control”.
It was that last phrase that got the debate going on the show I was listening to. Person 1 argued that it annoyed him that people kept dropping the “women” part of the quote. Person 2 shot back that it actually drove him nuts that people felt the need to add it. He argued that for every straight female using contraception, there was by definition a straight man using it. Unless one presumed a statistically significant number of women were misleading their partners, 98% of Catholic men were also using birth control (of course, even if they were being misled, they were actually still using it…just not knowingly). Since according to Catholic doctrine the contraception mandate is for both genders, both parties are therefore guilty.
I liked the debate, and would be totally fascinated to hear the numbers on men who have used (or had a partner who used) contraception. I am curious if a significant number don’t know, or would claim not to know. I still think that clarifying “women” in the quote is fine, as it’s who the study was actually done on. In my mind extrapolation should always be classified as extrapolation, not an actual finding.
Also of note, this was an in-person survey. That’s always useful to realize that every answer given in a survey like this had to verbalize their answers to another person….important when the topic is anything highly subject to social pressures. For a further breakdown of issues with that study, see here.
Beware the Adjective
My tax return showed up in my bank account this weekend, which is always nice (even if it was my money to begin with). It brought to mind a few months back when people were big on the “50% of American households don’t pay any federal income tax” statistic.
Now, that was an interesting statistic, and one that no doubt caused a lot of emotion. I mean, heck, this is my percent breakdown of taxes paid for 2011 (excluding sales-linked taxes…that retrospective would have taken all week):
Edit: My labels got a little hinky, so assume federal tax = federal income tax and state tax = state income tax. So yes, life would have been a great deal cheaper if I could have avoided federal income tax.
Anyway, I was thinking about this when I stumbled across this chart:
Along with this post explaining that many of the households not paying taxes were actually older workers. Interesting, but economic data is so easily manipulated it doesn’t normally catch my attention (example: no where on this graph does it indicate how large each population slice is…I’m sure there are far fewer people represented at the end of the graph than at the middle).
Anyway, what this jogged my memory about was how this statistic got quoted by many at the time. Rick Warren was one of the more notable examples, but many people made the mistake of stating “half of all Americans pay no taxes”. The “Federal Income” part of that phrase makes a huge difference.
I’m certainly not saying that everyone who misquotes a stat does so intentionally. Many times it’s innocent, and thus it’s something to keep in mind when you hear a crazy statistic from anything but the source. Politicians and other public speakers do just flat out miss words sometimes. There are some pretty horrifying stats out there that become much more reasonable when the correct modifiers are put back in their place.
Easter Infographic
Most infographic’s are not terribly accurate or useful. However, it’s Easter, and this is pretty:
Friday links for fun – 4.6.12
Two fun articles taking on bad data:
This one covers everything I will probably ever say in this blog, but with less pizzazz.
This one is trying to stop bad data before it starts. Don’t try to make things in to a scientific experiment if you have to fudge around things to do it. Just call it a model. I like that.
graph paper diaries 